Paraffin wax stabilized with a 2, 4, 5, trihydroxyphenyl ketone



United States Patent PARA'FFIN WAX STABILIZED WITH A 2,4,5, TRI-HYDROXYPHENYL KETONE Alan Bell, M. B. Knowles, and Clarence E.Tholstrup,

Kingsport, Tenn., assignors to Eastman Kodak Company, Rochester, N. Y.,a corporation of New Jersey No Drawing. Application July 2, 1954 SerialNo. 441,153

6 Claims. (Cl. 106-270) This application is a continuation-in-part ofour application Serial No. 302,412, filed August 2, 1952, now U. S.Patent 2,759,828, issued August 21, 1956, which covers the stabilizationof fats, oils, etc. with some of the compounds disclosed herein and someother compounds.

This invention relates to novel compounds for the stabilization of fats,oils and other organic materials subject to deterioration, e. g.paraffin wax, etc. These compounds are COR derivatives of1,2,4-trihydroxybenzene wherein R is defined below.

The object of our invention is wax stabilized with a 2,4,5, which isparticularly useful in and oils.

In accordance with our invention, novel compounds are provided whichconsist of those selected from the group having the following formula:

to provide a parafiin trihydroxyphenyl ketone the stabilization of fatswhich can probably be more specifically written as follows:

CO-R

wherein R represents a member selected from the group consisting of analkyl radical containing from 2 to 20 carbon atoms, a cycloalkyl radicalcontaining from 6 to carbon atoms, an alkenyl radical containing from 2to 10 carbon atoms, an aralkyl radical containing from 7 to 20 carbonatoms and a furyl radical. The position of the substituent CO-R on thebenzene ring appears to be that shown in the second formula. The namesof the various novel compounds will be based on that assumption. Ofcourse it is obvious that the processes for producing these compoundsresult in the formation of small amounts of isomers other than thosecovered by the second formula given above.

Examples of compounds which come within the scope of the above formulainclude 2,4,5-trihydroxybutyrophenone, 2,4,5-t rihydroxyvalerophenone,2,4,5-trihydroxyphenyl furyl ketone,2,4,5-trihydroxy-u-ethylbutyrophenone, 2,4,S-trihydroxycaprophenone,2,4,5-trihydroxya-ethylcaprophenone, 2,4,5-trihydroxyphenylomegaphenyl-n-decyl ketone, 2,4,5-trihydroxypheny1 octyl ke- 2,848,345Patented Aug. 19, 1958 hereinbelow relating to the antioxidantproperties of I such compounds.

It is known that 1,2,4-trihydroxybenzene can be employed for thestabilization of fats and vegetable oils. There is no suggestion,however, in the prior art that derivatives of this compound would alsobe useful as antioxidants for fats, vegetable oils and other organicmaterials subject to deterioration. The introduction of the group, COR(wherein R is defined above) on the benzene ring of1,2,4-trihydroxybenzene has been found to result in the formation ofcompounds which have excellent antioxidant properties. This was whollyunexpected and unpredictable especially since the introduction of CORsubstituents on the nucleus of hydroquinone gives compounds with verylittle antioxidant value. The following table presents data relating tothe effect of the introduction on the nucleus of hydroquinone of a CORradical wherein the radical substituted is CO(CH CH This data is basedon tests conducted under the active oxygen method (AOM) which isdescribed in the parent application mentioned above.

These tests were conducted employing lard as the substrate which had anAOM value of 4 hours (lard A) and 12.5 hours (lard B) when it containedno antioxidant. The concentration in each instance was 0.02 percent byweight of the antioxidant in the lard.

The difierence between the dihydroxy and the trihydroxy derivativescontaining a -COR radical is clearly evident, as indicated by the abovetable.

The introduction of the -COR substituent on to the nucleus of1,2,4-trihydroxybenzene gives products which have many advantages asantioxidants over 1,2,4-trihydroxybenzene itself. Thus the compounds ofantioxidant value described in this invention are stable to air, areless water-soluble and more fat-soluble.

If R were a methyl radical in the above formula the compound2,4,S-trihydroxyacetophenone would not be as satisfactory in severalimportant respects as are the compounds covered by the above formula inwhich R contains 2 or more carbon atoms. One of the problems which isquite important in regard to the use of phenolic type antioxidants inedible fats and oils is the discoloration that often develops when thestabilized product is in contact with'iron and water. When R is methyl,discoloration develops quite rapidly and becomes very intense. When Rcontains two or more carbon atoms the color formation is lesssignificant and disappears as the number of carbon atoms becomesgreater. Thus 2,4,5- trihydroxy butyrophenone is satisfactory for usewhereas 2,4,S-trihydroxyacetophenone develops very bad color formation.For this reason, 2,4,5-trihydroxyacetophenone is not satisfactory foruse commercially as an antioxidant for edible fats and oils where thepresence of an acceptable coloris important. There is another imf 3portant property in which 2, 4, S-trihydroxyacetophenone is inferior tothe higher homologs. In trying tests, fats stabilized with2,4,S-trihydroxyacetophenone darkened more intensely and more quicklythan the higher homologs. This property is also objectionable fom acommercial standpoint.

The compounds described as antioxidants in accordance with our inventioncan also be advantageously employed for the stabilization of otherorganic compounds subject to deterioration in addition to fats and oils,e. g. gasoline, lubricating compositions, transformer oil, fuel oil,carotene containing materials, plastic compositions, paraffin wax,tallows, suet, vitamins, essential oils such as citrus oils, polymericmaterials such as polyethylene, cellulose esters, polyesters, etc.

The advantages of the higher homologs covered by the invention ascompared to 2,4,S-trihydroxyacetophenone may be summed up as follows:

(a) Improved water and fat solubility characteristics (b) Improvedproperties in respect to color formation in the presence of iron andwater (c) Less darkening of the stabilized fat during frying (d) Greaterefiectiveness in stabilizing paraflin Wax.

The advantages of the compounds of this invention in stabilizing hotparafim wax are illustrated by these AOM values (hours) based on the useof 0.01% of the antioxidant in parafiin wax at 150 C.; these data arebased on determinations made at 50 m. eq. of peroxide:

AOM Keeping Quality (Hours) Compound (0.01%)

The above data cover a representative group from thirty compoundsevaluated in a series of tests which showed2,4,5-trihydroxybutyrophenone to be the most effective compoundevaluated.

When employed as antioxidants for fats, oils, and the like, fractions ofa percent of the compounds of this invention can be incorporated intosuch materials as lard, cottonseed oil, peanut oil, paraflin, etc., byadmixing the antioxidant with the fat, oil or other substrate whereby asolution of the antioxidant in the substrate is obtained. Alternatively,the antioxidant can be blended with suitable solvents to form anantioxidant solution. Examples of such solvents include glycerin,propylene glycol, hexane, etc., or other similar solvents which areinert insofar as concerns both the antioxidant and the other componentsof the ultimately prepared stabilized substrate. Such antioxidantsolutions can be more readily dissolved in the substrate to bestabilized with less necessity for prolonged mixing of the substratewith the undissolved antioxidant. Similarly, synergists can be admixedwith the fats or oils along with the dry antioxidant compounds of thisinvention or, in order to facilitate the incorporation of theantioxidant and the synergist into the substrate, tllljey can both bedissolved in such solvents as described a ove.

The stabilized substrates incorporating the novel compounds provided bythis invention advantageously contain from about 0.001% toabout 1.0% byweight of a novel compound having the structural formula set forthhereinabove. These stable products include combinations of such novelcompounds with other antioxidants, e. g. isomers of tert.butyl-p-hydroxyanisole, propyl gallate, etc., some of which combinationsof antioxidants may be synergistic in nature. Such products include fatsand oils stabilized with from about 0.001% to about 1.0% by weight of anantioxidant defined by the depicted general formula admixed with fromabout 0.0005% to about 0.1% by weight of the fat, oil, or othersubstrate of a synergist, e. g. citric acid, tartaric acid, phosphoricacid, ascorbic acid, propyl gallate, etc.

Procedures for preparing the novel compounds of the type disclosedhereinabove as antioxidants are set forth in the examples which aregiven below. The procedures set forth in the following examples can bereadily adapted to prepare any of the compounds included in the generalformula.

The following examples will serve to illustrate advantageous processesfor the preparation of antioxidant compositions coming within the scopeof this invention:

Example 1.-2,4,5-trihydr0xybutyrophenone A Fries rearrangement wascarried out with 1,2,4-tributyroxybenzene by gradually adding 26 g. (0.2mole) of aluminum chloride to a solution of 67.2 g. (0.2 mole) of thetributyrate in 200 cc. of nitrobenzene. This mixture was left 16 hoursat room temperature, poured into 150 cc. of 10 percent hydrochloricacid, and steam distilled to remove butyric acid and nitrobenzene. Theresidue in the pot was cooled to 5 C. and a yellow oil was extractedwith ether. The ether extract was washed, dried, and then 100 cc. ofmethanol containing 5 g. of hydrogen chloride was added and the mixturewas boiled for a few minutes. The methanol was distilled OE and replacedwith benzene. This was again distilled to remove the last traces ofmethanol. The benzene solution (150 cc.) was finally cooled and thesolid which separated was recrystallized from hot water using charcoalto decolorize. The yield was 16 g. of a product which melted at 151-3 C.The calculated analysis for this compound (C1UH12O4) is C, 61.21; H,6.16; the actual analysis showed C, 61.31; H, 6.45.

1,2,4-tributyroxybenzene which is not known to have been described inthe prior art and which was employed above was prepared by a Thielereaction. Fifty-four grams (0.5 mole) of p-quinone was addedportion-wise at 40-50 C. with stirring to 210 g. (1.4 moles) of nbutyricanhydride containing 10 g. of concentrated sulfuric acid. After theaddition of p-quinone was complete, the mixture was allowed tospontaneously cool to 25 C. and was then poured into water. The solutionwas extracted with ether. The extract was washed with water, then withdilute soduim carbonate solution, and finally with water again anddistilled. The product distilled at 153-55" C. (0.08 mm.). The yield was150 g. percent).

Example 2.2,4,5-trihydroxybutyrophenone The product of Example 1 wasalso prepared in the following manner: Thirty-three grams (0.25 mole) ofaluminum chloride was added to a solution of 12.6 g. (0.1 mole) of1,2,4-trihydroxybenzene in 200 cc. of nitrobenzene. The mixture wascooled at 25 C. and 16 g. (0.1 mole) of n-butyric anhydride added. Thereaction mixture was then heated to 60 C. for 45 minutes. After cooling,cc. of ice-cooled 10 percent hydrochloric acid was added and the mixturesteam distilled to remove nitrobenzene. The pot residue, on cooling,deposited 12 g. (61 percent) of pure 2,4,5-trihydroxybutyrophenone.

Example 3.2,4,5-trihydr0xyis0butyrophenone v cooled, the residuecrystallized. Recrystallization from ethylene dichloride gave a productlight yellow in color and one which melted at 136-8 C. The yield was 12g. (31%). This compound, 2,4,S-trihydroxyisobutyrophenone, is not knownto have been described in the prior art.

Example 4.2,4,S-trihydroxycaprylophenvne This compound was prepared asin Example 3 using 25.2 g. (0.2 mole) of 1,2,4-benzenetriol, 300 ml. ofnitrobenzene, 40 g. (0.3 mole) of aluminum chloride, and 33 g. (0.2mole) of n-caprylyl chloride. The crude product was recrystallized oncefrom acetic acid-water and then from naphtha-butyl acetate; M. P.113-114" C.; yield, 15 g. (30%).

Example .-2,4,5-trihydroxystearophenone .This compound was prepared asin the preceding two examples (Examples 3 and 4) using identical molarratios of reactants. The crude product was decolon'zed in ethanolsolution then precipitated by adding a little water. Recrystallizationfrom carbon tetrachloride and then from methanol gave a light yellowproduct which melted at 118-119 C. The yield was 39.2 g. (50%).

Example 6.2,4,S-trihydroxycrotophenone This compound was prepared as inExample 3 using identical molecular proportions. Y The residue fromsteam distillation was blood red and crystallized to a mush only afterstanding at C. for several hours. This mush Was dissolved in methanoland thesolution treated with charcoal; the product precipitated by theaddition of water. Further purification was obtained by passing anacetone solution of the product through a short column of activatedalumina (Al-0101-P). The acetone solution was concentrated and waterthen added caused a light brown, crystalline material to separate; M. P.219-221 C.; yield 2 g. (5%). This compound, 2,4,5-trihydroxycrotophenonecan also be called 2,4,5-trihydroxyphenyl propenyl ketone.

Example 7.2,4,5-trz'hydr0xyphenyl furyl ketone A mixture consisting of0.1 gram mole of 1,2,4-trihydroxybenzene, 0.12 gram mole (16 grams) ofaluminum chloride and 200 cc. of nitrobenzene were warmed at about 60 C.for about 5 minutes with 0.1 gram mole of furoyl chloride. The mixturewas then decomposed with ice cold dilute hydrochloric acid. After steamdistillation to remove the nitrobenzene the residue was cooled and1,2,4-trihydroxybenzene monofuroate crystallized. The

Example 8.2,4,5-zrihydr0xy-a-ethylbutyrophenone This compound wasprepared as in Example 3 using 25.2 g. (0.2 mole) of 1,2,4-benzenetriol,300 ml. of nitrobenzene, 40 g. (0.3 mole) of aluminum chloride and 26.9g. (0.2 mole) of 2-ethylbutyryl chloride. The crude product was purifiedby crystallizing from acetic acid- Water and then from benzene-hexene. Ayield of 10 g. (22%) which melted at 123-4 C. was obtained.

Example 9.2,4,S-trihydrOxy-a-ethylcaprophenone This compound wasprepared as in the example shown above using the same molar ratios ofreactants. The crude product was purified by crystallizing frombenzene-hexane. A yield of 12%, which melted at 94-7 C., was obtained.

Example J0.-2,4,5-trihydroxylwarophen0ne This compound was prepared asin the above examples. I

The crude product was purified by crystallizing first from aceticacid-water and then from benzene-hexane; M. P. 119-121 C., yield 29%.

Example 11.-2,4,5-trihydr0xycapriphenone Example12.2,4,5-trihydroxy-a-phenylacetophenone This compound was prepared asin the above examples. The solvents used for purification werebenzene-ethanol then acetic acid-water. A yield of 20%, which melted at210-213 C., was obtained. Example 13.Cyclohexyl 2,4,5-trihydroxyphenylketone This compound was prepared as in the above examples. The crudeproduct was purified by crystallizing from benzene-methanol then fromethanol-water. A yield of 7.5%, which melted at 186-8 C., was obtained.

The above examples clearly indicate how the compounds of this inventioncan be prepared. By suitable modifications of the described procedures,any of the compounds coming within the scope of the above depictedformula can be similarly prepared.

The compounds prepared as described in the above examples can beemployed as antioxidants in lard and in some vegetable oils. Testsaccording to the active oxygen method have shown the effectiveness ofthese antioxidants. The results of some of these tests are set forth inthe following table. For comparison purposes several commercialantioxidants and other compounds are also included.

Inasmuch as it is well known in the art to employ antioxidants in thestabilization of fats, oils and other materials, it is not believednecessary to give numerous additional examples of how the antioxidantsof this invention can be blended with the various organic materials noradditional specific proportions which can be employed in the manypossible examples which would come Within the scope of the descriptionhereinabove. The data presented in the table below is based on testsconducted under equivalent conditions employing similar samples in eachinstance of lard except as indicated. Data concerning paraffin have beenpresented in a table above.

The procedure employed under the AOM (active oxygen method) is wellknown in the antioxidant art and is explained in the parent applicationSerial No. 302,412 referred to above.

A perusal of the data contained in the following table indicates thatthe novel antioxidants of this invention are, insofar as theirstabilization characteristics are concerned, clearly superior in lard,parafiin, etc. to many of the antioxidants which are commerciallyavailable such as tertiary butyl-p-hydroxyanisole (BHA), propyl gallate,etc. Moreover, other properties of these antioxidants render themsuperior to those known to the prior art, e. g. such properties assolubility in fats, freedom from discoloration, food processingcharacteristics, lack of taste effects, insolubility in water, etc.

Other antioxidants coming within the scope of the above depicted generalformula can be employed in a similar manner to obtain analogousadvantageous results in the same or in other substrates within the scopeof the preceding description of our invention.

A. O. M. DATA IN LARD A. O. M.-Value in Hr. at 0.02% Compound 5 Lard BLard G Control 12. 5 11.5 Fl'A 32 31 Propyl gallate 86 92 Cyclohexyl2,4,5'trihydr0xypheny1ketone... 87 1O2,4,5-Trihydroxy-a-phenylaeetophenone 120 a-Ethyl-2,4,fi-trihydroxybutyrophenone. 75 a-Ethyl-2,4,5-trihydroxyeaprophen0ne 692,4,fi-Trihydroxyeapriphenone. 106 2,4,5-Trihydroxylaurcphen0ne 1062,4,5-Trihydr0xybutyrophen0ne 160 2,4,5-Trihydroxycaprylophenone 1532,4,5-Trihydr0xyerot0phen0ne 2,4,s-Trihydroxyisoburyrophenone2,4,5-Trihydroxystearophen0ne- 2,4,5-Trihydr0xyphenyl fury] ketonewherein X represents a member selected from the group consisting of analkyl radical containing from 2 to 20 carbon atoms, a cycloalkyl radicalcontaining from 6 to 10 carbon atoms, an alkenyl radical containing from2 to 10 carbon atoms and an aralkyl radical containing from 7 to 20carbon atoms.

2. Stabilized parafiin wax as defined in claim 1 wherein the improvedantioxidant is 2,4,5-trihydroxy1aurophenone.

3. Stabilized parafiin wax as defined in claim 1 wherein the improvedantioxidant is 2,4,S-trihydroxyisobutyrophenone.

4. Stabilized paraflin wax as defined in the improved antioxidant is2,4,5-trihydroxybutyrophenone.

5. Stabilized parafiin wax as defined in claim 1 wherein the improvedantioxidant is 2,4,5-trihydroxypheny1 cyclohexyl ketone.

6. Stabilized paraflin wax as defined in claim 1 wherein the improvedantioxidant is 2,4,5-trihydroxycaprylophenone.

References Cited in the file of this patent UNITED STATES PATENTS2,034,024 Clarke Mar. 17, 1936 2,116,220 Shoemaker May 3, 1938 2,590,813Britton et al. Mar. 25, 1952 2,636,003 Capell et al Apr. 21, 19532,686,123 Campbell et a1. Aug. 10, 1954 2,686,812 Wynn et al Aug. 17,1954 2,694,014 Capell et a1. Nov. 9, 1954 OTHER REFERENCES Handbook ofPlastics, Simonds and Ellis (1943), pp. 311 and 312. Thompson: J our.Ind. & Eng. Chem, 42 (1950).

in claim 1 where-

1. STABLILIZED PARAFFIN WAX WHICH CONTAINS FROM ABOUT 0.001% TO ABOUTONE PERCENT BY WEIGHT OF AN IMPROVED ANTIOXIDANT HAVING THE FOLLOWINGFORMULA: